1. Field of the Invention
The present invention relates to an interchangeable lens camera in which a lens unit is detachable from a camera body, the camera body, and a method for determining the mounting of the lens.
2. Description of the Related Art
Interchangeable lens cameras, in which a lens unit having a photographing lens is detachable from a camera body, have come into widespread use. As such interchangeable lens cameras, generally, there are a single-lens reflex camera having a reflection mirror, which reflects light incident into the lens unit and guides the light into an optical viewfinder, and a mirrorless single-lens camera in which the reflection mirror is omitted. Further, not only interchangeable lens cameras in which an imaging device is provided in a camera body, but also interchangeable lens cameras in which the imaging device is provided in a lens unit have been known.
JP1990-149073A (JP-H02-149073A) discloses a camera in which the lens unit is detachable from the camera body configured such that when a control signal for requesting an initial value is sent from the camera body to the lens unit through a communication path, the number of the lens unit is sent back from the lens unit to the camera body, and then the camera body determines that the lens unit is normally mounted on the camera body if data communication is performed normally.
JP1995-114087A (JP-H07-114087A) discloses a camera in which the lens unit is detachable from the camera body, the camera including a lens detection terminal dedicated to detection of the lens unit. In the case where the lens unit is not mounted, a resistance value of the lens detection terminal is increased (becomes a high level) by a pull-up resistor. In the case where the lens unit is mounted, the lens detection terminal is connected to a ground terminal of the camera body through the lens unit. A central processing unit (CPU) of the camera body determines whether the lens unit is mounted by detecting a change in the resistance value of the lens detection terminal from a high level, at which the resistance value is high, to a low level at which the resistance value is low.